High energy density of uranium is one of key advantages of nuclear energy
To maintain chain reaction needed for operating the reactor, uranium must have sufficiently high concentration of a specific isotope, uranium-235. Uranium is enriched in specific facilities, for use in a nuclear reactor. Enriched uranium is converted into dust which is then compressed into uranium pellets. One uranium pellet, the size of a tip of man's little finger, produces as much energy as one ton of coal, 560 litres of oil or 480 cubic meters of natural gas.